1. Field of the Invention
The present invention relates to mobility between an IEEE 802.16m cell and a non-802.16m cell, and more particularly, to a method of, at a mobile station, scanning neighbor base stations of heterogeneous cells using recommended cells decided by a base station on the basis of location based service (LBS) information of the mobile station.
2. Discussion of the Related Art
An IEEE 802.16m system supports communication between a homogeneous cell and a heterogeneous cell, but the existing IEEE 802.16e system supports only communication between homogeneous cells.
FIG. 1 is a view showing an example of a process of performing cell selection at a mobile station in the IEEE 002.16e system.
When the mobile station is powered on, the mobile station receives downlink/uplink (DL/UL) map and downlink channel descriptor/uplink channel descriptor (DCD/UCD) messages from a current cell, acquires UL/DL parameters, and performs synchronization with a base station. The mobile station performs an initial ranging process and measures a channel state (a carrier to interface and noise ratio (CINR) and a received signal strength indication (RSSI)) of the current cell after performing the synchronization with the base station. If the channel quality of the current cell measured by the mobile station is decreased to a specific threshold value or less, the mobile station scans neighbor cells. If it is determined that a neighbor cell having channel quality higher than that of the current cell is present by the scanned result, a neighbor cell having a highest channel quality is selected. After moving to a new cell, the mobile station performs synchronization with a base station and performs an initial ranging process, similar to the previous cell.
In order to enable the mobile station to perform cell selection between heterogeneous cells, a process of scanning the heterogeneous cells should be first performed. Unlike the cell selection between homogeneous cells, since several heterogeneous cells should be scanned in order to support the cell selection between the heterogeneous cells, a time consumed for scanning is increased and latency of handover and cell selection is increased.